Chelsea had not lost at their west London home all season and it looked like that trend would continue after they went 2-0 ahead following goals from Gary Cahill and Ramires.

However Jon Stead pulled a goal back for Bradford before the break, while Felipe Morais equalised and Halliday gave the visitors the lead.

The hosts pushed forward but it was Bradford who finished the scoring through Mark Yeates.

Chelsea boss Jose Mourinho was gracious in defeat as he went into the Bradford dressing room after the game to congratulate the players.

Jose Mourinho has just been in an ecstatic away dressing room to congratulate every City player and staff member. A real touch of class.

— Bradford City AFC (@officialbantams) January 24, 2015

“We are speechless,” Halliday told talkSPORT. “Two nil down against arguably the best team in Europe and to come back like we did – you will struggle to see a better performance at Stamford Bridge this season.

“Before kick-off we knew we were capable, but we went 2-0 down so early on.

“It went through our mind to get the next goal and when we did we knew we had to show more intent and less respect to Chelsea in the second half. We were outstanding in the second half.”

Bradford boss Phil Parkinson led his side on their epic journey all the way to the Capital One Cup final at Wembley two years ago, and Halliday made comparisons with this FA Cup run.

He added: “With the run we have had we had confidence to perform on this platform. A few boys who were on (the) league cup run said they felt same kind of spirit in this group.

“It’s another step. Hopefully (we will) get (a) fortunate draw.”

Parkinson is no stranger to giant killings after that league cup final run in 2013, where they saw off then Premier League side Wigan, Arsenal and Aston Villa.

“Would many come to Stamford Bridge and play two up front?” Halliday added.

“The attacking intent we showed is testament to the manager, a lot would come here and play behind the ball.”